A plasma-treated ultrathin polystyrene (PS) film surface was explored as a simple, robust, and lo... more A plasma-treated ultrathin polystyrene (PS) film surface was explored as a simple, robust, and low-cost surface chemistry solution for protein biosensing applications. This surface could dramatically improvethe binding efficiency of the protein–protein interactions, which is defined as the binding signal perimmobilized ligand. The PS-modified protein biosensor was readily fabricated by spin coating and plasmatreatment. Various parameters for fabrication, including the concentration of the PS solution, rate of spincoating, and duration of plasma treatment, were systematically optimized based on the improvementof fluorescence signal yielded by the microfluidic network-aided fluorescence immunoassay. The per-formance of the label-free protein detection on the optimized surfaces was further evaluated by surfaceplasmon resonance imaging (SPRi). PS surfaces with optimal fabrication parameters exhibited up to an620% enhancement of the protein binding response and approximately 210% of the protein binding perimmobilized protein ligand compared with a self-assembled monolayer (SAM) surface of 11-mercaptoundecanoic acid (MUA). The relationship between the fabrication parameters used and changes to thesurface chemistry and the morphological properties were characterized with atomic force microscopy(AFM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). Itwas revealed that the morphological changes observed in the plasma-treated PS film were the dominantfactor for the improvement of the protein bioassay performance, rather than the chemical changes.
Proceedings of the National Academy of Sciences of the United States of America, Aug 29, 2017
Chemical modifications on histones and DNA/RNA constitute a fundamental mechanism for epigenetic ... more Chemical modifications on histones and DNA/RNA constitute a fundamental mechanism for epigenetic regulation. These modifications often function as docking marks to recruit or stabilize cognate "reader" proteins. So far, a platform for quantitative and high-throughput profiling of the epigenetic interactome is urgently needed but still lacking. Here, we report a 3D-carbene chip-based surface plasmon resonance imaging (SPRi) technology for this purpose. The 3D-carbene chip is suitable for immobilizing versatile biomolecules (e.g., peptides, antibody, DNA/RNA) and features low nonspecific binding, random yet function-retaining immobilization, and robustness for reuses. We systematically profiled binding kinetics of 1,000 histone "reader-mark" pairs on a single 3D-carbene chip and validated two recognition events by calorimetric and structural studies. Notably, a discovery on H3K4me3 recognition by the DNA mismatch repair protein MSH6 in Capsella rubella suggests a m...
ABSTRACT This paper mainly describes that the effective index perturbation (EIP) technique in com... more ABSTRACT This paper mainly describes that the effective index perturbation (EIP) technique in combination with two-dimensional (2D)/three-dimensional (3D) PWE methods predicts resonant mode frequencies and mode patterns for the L3 photonic crystal slab cavity, which substantially reduces the computation time and computer memory without losing accuracy. The simulation results show that when the perturbed effective index by matching dielectric band edge is used, the fundamental resonant mode has small calculation frequency error; however, when the effective index obtained by the standard effective index method (EIM) is used, it is appropriate for predicting higher-order resonant modes, and the micro-photoluminescence experiments verify the predictions of the theoretical model. In addition, mode profiles of the L3 cavity with both the displacement of the end-holes and the base cavity structure can also be accurately predicted.
A novel surface plasmon resonance imaging (SPRi) biosensor based on waveguide coupled surface pla... more A novel surface plasmon resonance imaging (SPRi) biosensor based on waveguide coupled surface plasmon resonance (WCSPR) measurements is reported. Simply fabricated by gold evaporation deposition and polymer spin-coating, the WCSPR chips can be easily adapted on an commercial SPRi monitoring instrument. The chips were designed by using Fresnel method and fabricated according to its optimized design, the calculation and experimental results fits well. Over an 8 mm × 8 mm rectangle imaging area, the WCSPR chips realized about 52% increase of sensitivity, 57% enhancement of resolution and 55% improvement of signal to noise ratio compared to conventional SPR chips. Furthermore, high throughput protein-protein interaction analyses based on WCSPR chips were successfully accomplished by applying Protein A and rabbit antibody interaction in an array format. The reflectivity responses observed from the WCSPR chips were about 50% higher than the conventional SPR chip while the binding kinetic parameters were within the same range as with conventional SPR chip. (J. Zhu). 1 Equal contribution, Zhiyou Wang designed and fabricated WCSPR chips, Lusheng Song performed the parameters analysis of the WCSPR chips and the applications for high-throughput bio-interaction measurements. 0925-4005/$ -see front matter His current study is focused on optical sensing, material fabrication process, research and application of new SPR structure to imaging technique. . His current study is focused on microfluidic devices and biosensors.
ABSTRACT The label-free and sensitive detection of small molecule drugs on SPRi is still a challe... more ABSTRACT The label-free and sensitive detection of small molecule drugs on SPRi is still a challenging task, mainly due to the limited surface immobilization capacity of the sensor. In this research, a dextran hydrogel coated gold sensor chip for SPRi was successfully fabricated via photo-cross-linking for enhanced surface immobilization capacity. The density of the dextran hydrogel was optimized for protein immobilization and sensitive small molecule detection. The protein immobilization capacity of the hydrogel was 10 times greater than a bare gold surface, and 20 times greater than an 11-mercaptoundecanoic acid (MUA) surface. Such a drastic improvement in immobilization capacity allowed the SPRi sensor to detect adequate response signals when probing small molecule binding events. The binding signal of 4 nM liquid-phase biotin to streptavidin immobilized on dextran surface reached 435 RU, while no response was observed on bare gold or MUA surfaces. The dextran hydrogel coated SPRi sensor was also applied in a kinetic study of the binding between an immunosuppressive drug (FK506) and its target protein (FKBP12) in a high-throughput microarray format. The measured binding affinity was shown to be consistent with reported literature values, and a detection limit of 0.5 nM was achieved.
Accurate measurement of inter-peptide interactions is beneficial for in-depth understanding disea... more Accurate measurement of inter-peptide interactions is beneficial for in-depth understanding diseaserelated protein folding and peptide aggregation, and further for designing and selecting potential peptide drugs to the target antigen. Herein, we demonstrate a 3D polyrotaxane (PRX) surface for detecting peptides interactions by surface plasmon resonance imaging (SPRi). This surface is supramolecular selfassembly monolayer (SAM) structure fabricated by threading α-cyclodextrans (α-CD) through a linear polyethylene glycol (PEG) chain fixed on gold chip surface to form pseudopolyrotaxane, and further capping the pseudopolyrotaxane with bulky terminated group to form PRX film. The hydroxyl groups of α-CD can provide more active sites to increase molecules immobilization density, and PEG chain has unique protein non-fouling feature. We chose Alzheimer's disease marker β-amyloid 40 (Aβ40) as model peptide, and detected the interaction between it and its inhibitors KLVFFK6 by SPRi. As a striking result, the specific adsorption of KLVFFK6 solution at the concentration of 352 μM on Aβ40-PRX was 700 RU, whereas PEG SAM surface gave no significant binding. Interaction between other lower molecular weight peptides was detected via PRX surface, and the relatively weak interactions (K D ¼1.73 Â 10 À 4 M) between LPFFD (Mw ¼ 0.6 kDa) and amylin20-29 (Mw¼ 1.0 kDa) are successfully detected.
A plasma-treated ultrathin polystyrene (PS) film surface was explored as a simple, robust, and lo... more A plasma-treated ultrathin polystyrene (PS) film surface was explored as a simple, robust, and low-cost surface chemistry solution for protein biosensing applications. This surface could dramatically improvethe binding efficiency of the protein–protein interactions, which is defined as the binding signal perimmobilized ligand. The PS-modified protein biosensor was readily fabricated by spin coating and plasmatreatment. Various parameters for fabrication, including the concentration of the PS solution, rate of spincoating, and duration of plasma treatment, were systematically optimized based on the improvementof fluorescence signal yielded by the microfluidic network-aided fluorescence immunoassay. The per-formance of the label-free protein detection on the optimized surfaces was further evaluated by surfaceplasmon resonance imaging (SPRi). PS surfaces with optimal fabrication parameters exhibited up to an620% enhancement of the protein binding response and approximately 210% of the protein binding perimmobilized protein ligand compared with a self-assembled monolayer (SAM) surface of 11-mercaptoundecanoic acid (MUA). The relationship between the fabrication parameters used and changes to thesurface chemistry and the morphological properties were characterized with atomic force microscopy(AFM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). Itwas revealed that the morphological changes observed in the plasma-treated PS film were the dominantfactor for the improvement of the protein bioassay performance, rather than the chemical changes.
A plasma-treated ultrathin polystyrene (PS) film surface was explored as a simple, robust, and lo... more A plasma-treated ultrathin polystyrene (PS) film surface was explored as a simple, robust, and low-cost surface chemistry solution for protein biosensing applications. This surface could dramatically improvethe binding efficiency of the protein–protein interactions, which is defined as the binding signal perimmobilized ligand. The PS-modified protein biosensor was readily fabricated by spin coating and plasmatreatment. Various parameters for fabrication, including the concentration of the PS solution, rate of spincoating, and duration of plasma treatment, were systematically optimized based on the improvementof fluorescence signal yielded by the microfluidic network-aided fluorescence immunoassay. The per-formance of the label-free protein detection on the optimized surfaces was further evaluated by surfaceplasmon resonance imaging (SPRi). PS surfaces with optimal fabrication parameters exhibited up to an620% enhancement of the protein binding response and approximately 210% of the protein binding perimmobilized protein ligand compared with a self-assembled monolayer (SAM) surface of 11-mercaptoundecanoic acid (MUA). The relationship between the fabrication parameters used and changes to thesurface chemistry and the morphological properties were characterized with atomic force microscopy(AFM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). Itwas revealed that the morphological changes observed in the plasma-treated PS film were the dominantfactor for the improvement of the protein bioassay performance, rather than the chemical changes.
Proceedings of the National Academy of Sciences of the United States of America, Aug 29, 2017
Chemical modifications on histones and DNA/RNA constitute a fundamental mechanism for epigenetic ... more Chemical modifications on histones and DNA/RNA constitute a fundamental mechanism for epigenetic regulation. These modifications often function as docking marks to recruit or stabilize cognate "reader" proteins. So far, a platform for quantitative and high-throughput profiling of the epigenetic interactome is urgently needed but still lacking. Here, we report a 3D-carbene chip-based surface plasmon resonance imaging (SPRi) technology for this purpose. The 3D-carbene chip is suitable for immobilizing versatile biomolecules (e.g., peptides, antibody, DNA/RNA) and features low nonspecific binding, random yet function-retaining immobilization, and robustness for reuses. We systematically profiled binding kinetics of 1,000 histone "reader-mark" pairs on a single 3D-carbene chip and validated two recognition events by calorimetric and structural studies. Notably, a discovery on H3K4me3 recognition by the DNA mismatch repair protein MSH6 in Capsella rubella suggests a m...
ABSTRACT This paper mainly describes that the effective index perturbation (EIP) technique in com... more ABSTRACT This paper mainly describes that the effective index perturbation (EIP) technique in combination with two-dimensional (2D)/three-dimensional (3D) PWE methods predicts resonant mode frequencies and mode patterns for the L3 photonic crystal slab cavity, which substantially reduces the computation time and computer memory without losing accuracy. The simulation results show that when the perturbed effective index by matching dielectric band edge is used, the fundamental resonant mode has small calculation frequency error; however, when the effective index obtained by the standard effective index method (EIM) is used, it is appropriate for predicting higher-order resonant modes, and the micro-photoluminescence experiments verify the predictions of the theoretical model. In addition, mode profiles of the L3 cavity with both the displacement of the end-holes and the base cavity structure can also be accurately predicted.
A novel surface plasmon resonance imaging (SPRi) biosensor based on waveguide coupled surface pla... more A novel surface plasmon resonance imaging (SPRi) biosensor based on waveguide coupled surface plasmon resonance (WCSPR) measurements is reported. Simply fabricated by gold evaporation deposition and polymer spin-coating, the WCSPR chips can be easily adapted on an commercial SPRi monitoring instrument. The chips were designed by using Fresnel method and fabricated according to its optimized design, the calculation and experimental results fits well. Over an 8 mm × 8 mm rectangle imaging area, the WCSPR chips realized about 52% increase of sensitivity, 57% enhancement of resolution and 55% improvement of signal to noise ratio compared to conventional SPR chips. Furthermore, high throughput protein-protein interaction analyses based on WCSPR chips were successfully accomplished by applying Protein A and rabbit antibody interaction in an array format. The reflectivity responses observed from the WCSPR chips were about 50% higher than the conventional SPR chip while the binding kinetic parameters were within the same range as with conventional SPR chip. (J. Zhu). 1 Equal contribution, Zhiyou Wang designed and fabricated WCSPR chips, Lusheng Song performed the parameters analysis of the WCSPR chips and the applications for high-throughput bio-interaction measurements. 0925-4005/$ -see front matter His current study is focused on optical sensing, material fabrication process, research and application of new SPR structure to imaging technique. . His current study is focused on microfluidic devices and biosensors.
ABSTRACT The label-free and sensitive detection of small molecule drugs on SPRi is still a challe... more ABSTRACT The label-free and sensitive detection of small molecule drugs on SPRi is still a challenging task, mainly due to the limited surface immobilization capacity of the sensor. In this research, a dextran hydrogel coated gold sensor chip for SPRi was successfully fabricated via photo-cross-linking for enhanced surface immobilization capacity. The density of the dextran hydrogel was optimized for protein immobilization and sensitive small molecule detection. The protein immobilization capacity of the hydrogel was 10 times greater than a bare gold surface, and 20 times greater than an 11-mercaptoundecanoic acid (MUA) surface. Such a drastic improvement in immobilization capacity allowed the SPRi sensor to detect adequate response signals when probing small molecule binding events. The binding signal of 4 nM liquid-phase biotin to streptavidin immobilized on dextran surface reached 435 RU, while no response was observed on bare gold or MUA surfaces. The dextran hydrogel coated SPRi sensor was also applied in a kinetic study of the binding between an immunosuppressive drug (FK506) and its target protein (FKBP12) in a high-throughput microarray format. The measured binding affinity was shown to be consistent with reported literature values, and a detection limit of 0.5 nM was achieved.
Accurate measurement of inter-peptide interactions is beneficial for in-depth understanding disea... more Accurate measurement of inter-peptide interactions is beneficial for in-depth understanding diseaserelated protein folding and peptide aggregation, and further for designing and selecting potential peptide drugs to the target antigen. Herein, we demonstrate a 3D polyrotaxane (PRX) surface for detecting peptides interactions by surface plasmon resonance imaging (SPRi). This surface is supramolecular selfassembly monolayer (SAM) structure fabricated by threading α-cyclodextrans (α-CD) through a linear polyethylene glycol (PEG) chain fixed on gold chip surface to form pseudopolyrotaxane, and further capping the pseudopolyrotaxane with bulky terminated group to form PRX film. The hydroxyl groups of α-CD can provide more active sites to increase molecules immobilization density, and PEG chain has unique protein non-fouling feature. We chose Alzheimer's disease marker β-amyloid 40 (Aβ40) as model peptide, and detected the interaction between it and its inhibitors KLVFFK6 by SPRi. As a striking result, the specific adsorption of KLVFFK6 solution at the concentration of 352 μM on Aβ40-PRX was 700 RU, whereas PEG SAM surface gave no significant binding. Interaction between other lower molecular weight peptides was detected via PRX surface, and the relatively weak interactions (K D ¼1.73 Â 10 À 4 M) between LPFFD (Mw ¼ 0.6 kDa) and amylin20-29 (Mw¼ 1.0 kDa) are successfully detected.
A plasma-treated ultrathin polystyrene (PS) film surface was explored as a simple, robust, and lo... more A plasma-treated ultrathin polystyrene (PS) film surface was explored as a simple, robust, and low-cost surface chemistry solution for protein biosensing applications. This surface could dramatically improvethe binding efficiency of the protein–protein interactions, which is defined as the binding signal perimmobilized ligand. The PS-modified protein biosensor was readily fabricated by spin coating and plasmatreatment. Various parameters for fabrication, including the concentration of the PS solution, rate of spincoating, and duration of plasma treatment, were systematically optimized based on the improvementof fluorescence signal yielded by the microfluidic network-aided fluorescence immunoassay. The per-formance of the label-free protein detection on the optimized surfaces was further evaluated by surfaceplasmon resonance imaging (SPRi). PS surfaces with optimal fabrication parameters exhibited up to an620% enhancement of the protein binding response and approximately 210% of the protein binding perimmobilized protein ligand compared with a self-assembled monolayer (SAM) surface of 11-mercaptoundecanoic acid (MUA). The relationship between the fabrication parameters used and changes to thesurface chemistry and the morphological properties were characterized with atomic force microscopy(AFM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). Itwas revealed that the morphological changes observed in the plasma-treated PS film were the dominantfactor for the improvement of the protein bioassay performance, rather than the chemical changes.
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Papers by Wenfei Zhou